The newly relegated teams score 0.49 more and allow 0.54 fewer goals per match which is an improvement in net goal differential of 1.03 per match. Teams that are promoted into the Premier League see their goal differential decrease by 1.15 per match so it appears that moving between these two leagues will have about a ±1.1 goal/match impact on goal differential.
Applying the rate changes from the above table to the results of the 2011 relegated teams will give us the following projections for their Championship performance in 2012:
West Ham United
The 80 points that I'm projecting for Birmingham and Blackpool will probably not be enough to earn a Top 2 finish and automatic promotion. Over the past 19 seasons, the teams that finished in the top 2 in the Championship have averaged 90 points. The teams that have finished second averaged 86 points. Only 4 teams out of 38 have earned auto-promotion with 80 or fewer points. I would expect that all three teams will vie for a playoff spot next season. The average points earned by teams that were promoted through the playoffs is 76.
I noted above that 27% of teams relegated to the Championship are able to turn around and earn promotion the following season. The rate at which teams promoted to the Premier get relegated the following season is 47%. So why would relegated teams that are dropping into a lower-level league be less likely to earn promotion? I think that there are two factors driving this:
- There are only two automatic promotion spots in the Championship. The third spot is contested by the four teams ranked 3rd through 6th. So that's three additional matches that would have to be played (the last of which has to be a victory) to earn promotion. These teams are pretty comparable so anything can happen and usually does.
- The loss in income that results from relegation often forces teams to sell key players to help stay profitable at the lower level. So as talent level diminishes, the chances of earning promotion also diminish.